Rafael Nadal edged out an inspired Daniil Medvedev in a five-set thriller, 7-5 6-3 5-7 4-6 6-4 to win the US Open and secure his 19th Grand Slam title.
Nadal clinched his fourth crown at Flushing Meadows following triumphs in 2010, 2013 and 2017 but it was not remotely easy, despite the fact that he comprehensively outplayed the controversial Russian for the first two sets.
After Roger Federer and world number one Novak Djokovic both crashed out before the last four the Spaniard was expected to take advantage, and he duly did to close the gap on the Swiss to just one Slam in their famous tallies.
Remarkably given his clay-court dominance, Nadal has joined only Jimmy Connors, John McEnroe, Pete Sampras and Federer as the only players to have won four or more US Open titles in the Open Era.
The 33-year-old stormed two-sets up in the showpiece match in New York as he outpowered and outmanoeuvred his opponent, but Medvedev roared back in unlikely fashion to force a deciding set.
The crowd inside Arthur Ashe could not believe their luck in witnessing a surprise classic after Nadal's convincing early advantage, and Medvedev relished the raucous atmosphere as he went for broke to stunning effect in the third set with little to lose.
Nadal lost his serve from 5-5, and that proved hugely significant as his opponent discovered amazing momentum and duly took the fourth set with another crucial break of serve, including a flurry of outrageous winners.
The Spaniard appeared shellshocked at times in the final set and was further rattled when the New York crowd took exception to some of his customary slow play with frequent booing.
Nadal eventually received a time violation when a break-point down in the second game of the decider, but that inspired him to hold in very emotional fashion.
Finally, the breakthrough came in an enthralling final set as Nadal broke at 2-2 with an unbelievable drop shot and winner to stamp his authority back on the match, but a second time violation and a subsequent double fault saw him hand the advantage back when serving for the match at 5-2 up.
Thereafter it was all about the Spanish superstar as he closed out victory with such decisiveness that Medvedev could only shake his head and accept that he had been beaten in a classic.
"This has been an amazing final," Nadal said. "It has been one of the most emotional nights of my tennis career. Thank you very, very much, everybody in this stadium.
"It's been amazing energy during both weeks. I think there isn??™t another stadium in the world that is more energetic than this one so many thanks for everything."
Medvedev, always entertaining, added: "First of all I just want to congratulate Rafa, 19th Grand Slam title is something unbelievable, outrageous. I want to congratulate him and his team, you guys are doing an amazing job. It's very tough to play against you.
"When I was looking on the screen and they were showing number one, number two, number 19, I was thinking if I won, what would they show?!"